KARAKTER EKOLOGI DAN FISIOLOGI BAKTERI PENGHASIL ACC DEAMINASE

UMI SALAMAH, Dr. Ir. Ngadiman, M. Si.; Prof. Ir. Triwibowo Yuwono, Ph. D.

2018 | Skripsi | S1 MIKROBIOLOGI PERTANIAN

Penurunan pertumbuhan dan produktivitas tanaman dapat disebabkan oleh cekaman lingkungan yang menginduksi sintesis etilen berlebih. Terdapat bakteri penghasil 1-aminocyclopropane-1-carboxylate deaminase (ACCD) yang mampu menurunkan kadar etilen tanaman dengan cara menguraikan prekusor etilen, 1-aminocyclopropane-1-carboxylic acid (ACC) menjadi ammonia dan alfa-ketobutirat. Penelitian ini bertujuan untuk mengetahui karakter ekologi (faktor pH, suhu, aerobisitas), dan fisiologi (pelarutan fosfat, penggunaan sumber karbon, antagonisme patogen), serta ketahanan terhadap logam berat bakteri penghasil ACCD. Karakterisasi ekologi dan fisiologi 13 strain bakteri dilakukan dengan metode kualitatif. Strain bakteri yang digunakan adalah Sphingobacterium multivorum BK1, Bacillus aryabhattai TW7, Pseudomonas putida KS16.2, Lysinibacillus pakistanensis PIC5, Pantoea dispersa CK4, Pantoea agglomerans KB6.2, Stenotrophomonas maltophilia PIR5, Stenotrophomonas maltophilia PCM8, Pseudomonas monteilii KS12, Enterobacter ludwigii KW3, Pseudomonas putida PIR 3C, Bacillus aryabhattai PIC11, dan Bacillus mycoides CBW2. Hasil penelitian menunjukkan bahwa strain bakteri tumbuh optimum pada pH 6-8, suhu 25-30 derajat celcius, dan bakteri bersifat aerob sampai fakultatif anaerob. Strain bakteri memiliki Indeks Pelarutan Fosfat antara 1,10-3,04. Semua strain bakteri tidak memiliki daya antagonistik terhadap Xanthomonas orzae pv. oryzae dan Ralstonia solanacearum. Semua strain bakteri dapat menggunakan glukosa, sukrosa, selulosa dan manitol sebagai sumber karbon dan energi. Strain bakteri memiliki toleransi terhadap Cr6+ antara 100-300 mg.L-1.

The decrease of plant growth and productivity may be due to environmental stress that induce excessive ethylene synthesis. ACCD (1-aminocyclopropane-1-carboxylate deaminase)-producing bacteria are known to decrease crop ethylene levels by converting the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) to ammonia and alpha-ketobutyrate. This study was aimed at understanding the ecological (pH, temperature, aerobicity), physiological (phosphate solubility, carbon sources utilization, pathogen antagonism) and heavy metal tolerance characters of ACCD-producing bacteria. Ecological and physiological characterisation of 13 ACCD-producing bacterial strains was conducted by qualitative method. The bacterial strains used were Sphingobacterium multivorum BK1, Bacillus aryabhattai TW7, Pseudomonas putida KS16.2, Lysinibacillus pakistanensis PIC5, Pantoea dispersa CK4, Pantoea agglomerans KB6.2, Stenotrophomonas maltophilia PIR5, Stenotrophomonas maltophilia PCM8, Pseudomonas monteilii KS12, Enterobacter ludwigii KW3, Pseudomonas putida PIR 3C, Bacillus aryabhattai PIC11, and Bacillus mycoides CBW2. It was observed that all bacterial strains demonstrated optimal growth at pH 6-8, temperature 25-30 derajat celcius, and oxygen requirement of aerobic to facultative anaerobic. It was also noted that all strains have Phosphate Solubilizing Index between 1,10-3,04. In terms of antagonistic properties, all bacterial strains were found incapable of inhibiting Xanthomonas orzae pv. oryzae and Ralstonia solanacearum growth. All bacterial strains were capable of using glucose, sucrose, cellulose and mannitol as the source of carbon and energy. In addition, all bacterial strains also demonstrated Cr6+ tolerance up to 100-300 mg.L-1.

Kata Kunci : cekaman lingkungan, ACC deaminase, karakter ekologi dan fisiologi